"The Boeing 737 that flew out of Moscow's Domodedovo airport with 44 passengers crashed onto the runway at Kazan airport on landing and burst into flames," Russia's Investigative Committee, which probes serious incidents, said in a statement.

The emergency situations ministry posted photographs of fragments of the plane scattered across the runway outside Kazan, which is around 720 kilometres (450 miles) east of Moscow in the Tatarstan region.

The 23-year-old plane, owned by Tatarstan Airlines, was making a second attempt to land, the spokesman for Russia's civil aviation authority, Sergei Izvolsky, told the Interfax news agency.

"We know for sure that when the plane made a second attempt at landing, for some reason, the plane hit the surface of the runway near the air traffic control tower, as a result of which the plane crashed and burnt."

The plane's black boxes have not yet been found, Izvolsky said.

Russian President Vladimir Putin expressed his "deep condolences to the relatives and loved ones of those who died in the plane crash at Kazan airport," the Kremlin said in a statement.

"After receiving a report on the air crash, the head of state ordered the government to urgently form a commission to investigate the reasons and circumstances of what happened."

Prime Minister Dmitry Medvedev wrote on Twitter: "With all my heart I grieve for the relatives, friends and loved ones of the victims. A terrible tragedy."

The emergency ministry named 44 victims, saying that six were still being identified. The airline named the chief pilot as 47-year-old Rustem Salikhov.

Among the dead was the 24-year-old son of the leader of the Tatarstan region, Irek Minnikhanov, the RIA Novosti news agency reported, citing the region's deputy prime minister.

The airline named two girls aged 11 and 15, as among those on the flight.

The head of the region's FSB security service, General-Lieutenant Alexander Antonov, also died in the crash, a member of the disaster management team told RIA Novosti.

Emergency landing last year

The Investigative Committee said an inquiry had been opened to determine whether there had been any "violation of aviation security rules" and added that several inspectors had been sent to the scene of the crash.